琼胶降解菌AT-22的筛选和产酶性质  

Selection and enzymetic study on an agarolytic bacterium AT-22

作　　者：汤海青[1] 管斌[1] 王雪鹏[1] 陈丽红[1] 欧昌荣[2] 胡文浪[1] 

机构地区：[1]中国海洋大学水产学院,山东青岛266003 [2]宁波大学生命学院,浙江宁波315211

出　　处：《中国水产科学》2005年第2期216-219,共4页Journal of Fishery Sciences of China

摘　　要：从青岛近海的红藻(Gelidiumamansii)中分离筛选到1株高活力的海洋琼胶降解菌AT 22,对其生长、产酶特性和酶活力影响因素进行初步研究。结果表明,AT 22所产琼胶酶为诱导酶,0 2%葡萄糖的添加对菌株产酶有抑制作用。该酶作用的最适pH值为6 0～7 0,最适温度为40℃,最适底物质量分数为1%～1 2%,Ca2+的添加对酶促反应有较强的促进作用,而Fe3+、Mn2+、Cu2+和Hg2+等有不同程度的抑制作用。The agar-decomposing strain AT-22 was isolated and selected from some species of red algae (Gelidium amansii) in the coastal water of Qingdao. The growth and enzymeology properties were studied. The results show that the strain is a gram-negative rod strain which grows singly,producing crater-like depression zones surrounding cenral colonies of strain AT-22 on the agar plate,and producing red pigment on the 226E culture medium. The agarase produced by AT-22 is an inducible enzyme. When growing in the liquid culture medium containing agar as sole carbon source,it breaks down the agar rapidly,causing the increase of reduced sugar concentration and decrease of fermentation medium mucosity,and the production of agarase reaches maximum at 36h. The enzyme producing ability will be restrained by addition of 0.2% glucose in culture medium containing 0.2% agar,whereas its growth will be stimulated abundantly at the same time. The agarase produced by strain AT-22 appears to be a very specific enzyme and not a nonspecific glycosidase,inactive against polysaccharides such as κ-carrageenan,cellulose and alginate. The optimal pH is at 6.0-7.0 and temperature 40℃,stable in the pH range of 6.0-7.0,and falling off rather rapidly over 50 ℃. The optimal concentration of agar substrate is 1.0%-1.2%,addition of Ca2+ will greatly promote the enzyme activity,whereas under the presence of Fe3+,Mn2+,Cu2+ and Hg2+. The agarase activity is reduced.

关 键 词：琼胶降解菌 诱导酶 酶学性质 

分 类 号：S986.2[农业科学—捕捞与储运]